d malloc

[seany via Digitalmars-d-learn]

consider this :

struct S
{
/* ... */

}

void main()
{
    ulong [] u;

    for(// ...
    {
       S s_instance;
       // fillup .. S.key = value;
       u ~= cast(ulong)*s_instance;
    }

}

however, the structs are being allocated to the same place. 
Because, Every time the iterator ends an iteration, seemingly, 
s_instance is collected as garbage.

A test produces output like this.
object : a of type : tensor is stored at : 140737373264752
object : b of type : tensor is stored at : 140737373264752
object : c of type : tensor is stored at : 140737373264752
object : d of type : tensor is stored at : 140737373264752

So I would like to know if there is a malloc alternative in D, 
which I can use to explicitely allocate memory to hold a struct, 
or any other variable , such that the garbage collector does not 
remove it automatically.